Kala-azar, also called visceral leishmaniasis or tropical splenomegaly, is a disease caused mainly by the protozoa Leishmania chagasi and Leishmania donovani , and occurs when the mosquito of the species Lutzomyia longipalpis, popularly known as straw mosquito or birigui, infected by one of the protozoa, bites the person and releases this parasite into the person's bloodstream, resulting in illness.
This type of leishmaniasis mainly affects children older than 10 years and adults who have some nutritional deficiency, such as lack of iron, vitamins and proteins, and live in places with poor sanitation and hygiene conditions. The most affected Brazilian region is the Northeast and it is believed that children are the most affected because they have more nutritional deficiencies, the immune system is not yet fully formed and they are more exposed to animals.
Main symptoms
After being bitten by the mosquito that transmits the disease, protozoa spread through the bloodstream and through organs responsible for the formation of blood cells and the body's immunity, such as spleen, liver, lymph nodes and bone marrow, causing the following symptoms:
- Chills and high fever, which comes and goes, of long duration; Enlarged abdomen, due to enlarged spleen and liver; Weakness and excessive tiredness; Weight loss; Paleness, due to anemia caused by the disease; Bleeding easier, by gums, nose or feces, for example; frequent infections, by viruses and bacteria, due to the loss of immunity; diarrhea.
Visceral leishmaniasis has an incubation period of 10 days to two years, and as it is not a common disease and its symptoms appear gradually, they can be confused with other diseases such as malaria, typhoid, dengue or Zika, for example. Therefore, in the presence of these symptoms, it is important to seek medical attention so that the diagnosis can be made and appropriate treatment started.
It should be remembered that skin lesions and ulcers are caused by another type of leishmaniasis, called cutaneous or cutaneous. Know what causes and how to identify cutaneous leishmaniasis.
How the transmission happens
The main reservoir of the protozoa responsible for the kala azar is the dogs and, therefore, they are also considered the main source of mosquito infection. That is, when the mosquito bites the infected dog, it acquires the protozoan, which develops in its organism and can be transmitted to the person through the mosquito bite. Not all dogs carry Leishmania chagasi or Leishmania donovani , which is more common in dogs that are not regularly dewormed or do not receive the ideal care.
When the parasite is in the mosquito's organism, it can easily develop and then go to the salivary glands. When the infected mosquito bites the person, it passes the parasite present in its salivary glands into the person's bloodstream, being easily spread by the organs.
Diagnosis of Calazar
The diagnosis of visceral leishmaniasis is made by parasitological examination, in which a culture of bone marrow, spleen or liver is made in order to observe one of the evolutionary forms of the protozoan. In addition, the diagnosis can be made through immunological tests, such as ELISA, or immunochromatographic tests, which are popularly known as rapid tests.
The disadvantage of immunological tests is that even after treatment, it is possible that there is still a sufficient amount of antibodies, indicating infection. However, in these cases, it is important that the doctor assesses the presence of symptoms, because if there are no symptoms, treatment is not indicated.
How the treatment is done
Treatment for kala azar should start as soon as possible and can be done with the use of specific medications, such as Pentavalent Antimonial Compounds, Amphotericin B and Pentamidine, which must be indicated by the doctor and used according to his / her instructions.
When starting treatment it is also important to take some precautions, such as the assessment and stabilization of clinical conditions, such as malnutrition and bleeding, in addition to the treatment of other infections that accompany it. It may be necessary to remain hospitalized for use of medications in the vein, but, in cases where the infection is stable and there is easy access to the hospital, the doctor may recommend treatment at home and go to the hospital for follow-up.
This disease must be treated quickly, as it worsens in a few days and therefore the affected person may suffer life-threatening complications such as lung infection, respiratory failure, digestive bleeding, circulatory failure or due to opportunistic infections, by viruses and bacteria. Find out more details about treatment for visceral leishmaniasis.
